Pneumatic bellows pump



Aug. 18, 1970 GROVE EI'AL 3,524,714

PNEUMATIC BELLOWS PUMP Filed Oct. 30, 1968 J6 mam/Mme l V 1+ T 8 Z INVENTOR R036??? 1?- 6801 5 CAP/FL do EVE) wgw United States Patent Ofice U.S. Cl. 417345 5 Claims ABSTRACT OF THE DISCLOSURE A bellows pumping system having a pair of bellows, the bellows being alternately pressurized and vented in such a manner as to maintain a continuous flow of fluid through an outlet.

BACKGROUND OF THE INVENTION This invention relates generally to pumps and, more particularly, to a bellows pumping system capable of pumping a fluid from a liquid reservoir to a high pressure outlet.

It has become necessary under certain conditions to pump fluid to a high pressure outlet such as a thrust chamber. Conventional pumps fail to meet the high standards set forth under the above-mentioned circumstance. For example, conventional pumps are extremely ineffective when it comes to pumping liquids which are corrosive, since the construction of a noncorrosive piston or rotor type pump may fall well without the bounds of a reasonable price range. Furthermore, the pumps heretofore in use require a substantial power source and cannot pump fluids at sufficient pressure when power supplies are limited. The conventional pumping systems now in use also require constant lubrication and maintenance and further cannot store liquids for great lengths of time.

SUMMARY OF THE INVENTION The bellows pumping system of the instant invention overcomes the shortcomings set forth above. The pumping apparatus of the surge type, exemplified by the diaphragm or bellows pump of the instant invention, finds application whenever it is necessary or desirable that the process fluid be isolated from contact with the piston,rotor or reciprocating drive shaft through shaft seal means. It is also useful for pumping fluids at very low rates as in bench-scale, semi-works and pilot plant process units. The pneumatic bellows pump of the instant invention can also be used when the liquid to be pumped is corrosive, where power supplies are limited, when long periods of storage are required and when lubrication is not available.

The pneumatic bellows pump of the instant invention has a gas source which supplies this gas under pressure to a valve. The low pressure gas is controlled by the valve which supplies pressure to one of a set of bellows, while simultaneously venting the pressure from the other of the set of bellows.

The pressurized bellows supplies a fluid through a check valve to an outlet. The bellows which is being vented is filled with the fluid through another check valve from a main fluid supply tank. A switch is mounted on each of the bellows housings and these switches are connected to the gas control valve. Each switch is capable, upon actuation, of reversing the operation of the gas control valve; in other words, indicating that one bellows is full of the fluid to be discharged, and the other has completed the required stroke for discharge. The signal generated by the switches is sent to the valve in order to simultaneously pressure one bellows while venting the other. A

3,524,714 Patented Aug. 18., 1970 small accumulator is placed in the discharge line to smooth out the pressure pulsations.

It is therefore an object of this invention to provide a pneumatic bellows pump which is capable of pumping any fluid and which can store this fluid for long time periods.

It is another object of this invention to provide a pneumatic bellows pump which does not require an external source of power except for control valve signals.

It is a further object of this invention to provide a pneumatic bellows pump which requires no lubrication.

It is still another object of this invention to provide a pneumatic bellows pump which operates independently of a gravitational field.

It is still a further object of this invention to provide a pneumatic bellows pump which is economical to produce and which utilizes conventional, currently available components that lend themselves to standard mass production manufacturing techniques.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing.

DESCRIPTION OF THE DRAWING The only figure of the drawing represents a fragmentary cross-sectional schematic view of the pneumatic bellows pump of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to the only figure of the drawing wherein the pneumatic bellows pump of this invention is designated by numeral 10. A regulated gaseous source such as nitrogen is fed into inlet tube 12 from source 13. The inlet tube 12 is connected to any suitable mechanical, electrical or fluid control valve 14. This valve 14 regulates the flow of gas into the bellows system 16.

The bellows system 16 is connected to the control valve 14 by a plurality of tubes 18 and 20. The bellows system 16 is made up of a pair of bellows 22 and 24 each sealed within its own tank or housing 26 and 28, respectively. Although only one pair of bellows are shown any suitable number of pairs of bellows may be used in conjunction with a suitable valve 14. The bellows 22 and 24 are made of any suitable light-Weight, non-corrosive material. Attached to each housing 26 and 28 and is a switch 30 and 32, respectively. The switches 30 and 32 are of any suitable construction such as electrical, pneumatic or mechanical and are connected in any suitable manner such as by an electrical circuit to the valve 14.

The fluid to be pumped through the system enters inlet tube 42 from fluid source 43. Valve 14 regulates the pressure of the gas from source 13. Gas under pressure is fed into one of the bellows housings 28, while the other housing 26 is simultaneously vented to atmosphere. For example, while gas under pressure is supplied to housing 28 through inlet 20, housing 26 is vented through tube 18 to the atmosphere by vent 19. The above action closes check valves 36 and 38. The bellows 24 supplies pressurized liquid to the outlet tube 44 through check valve 40, while bellows 22 is filling with liquid passing through check valve 34. As flow is supplied out of the liquid outlet port 46, bellows 24 moves downward and at a pre determined point 48 (as shown in the Figure) causes by any suitable switching arrangment 32 (such as by an electrically, pneumatically or mechanically operated siwtch) the gas control valve 14 to cycle so regulated gas is now supplied to housing 26 through tube 18 and housing 28 is vented to atmosphere through tube 20 and vent 21. This operation closes check valves 34 and 40 and supplies pressurized liquid to outlet port 46 through check valve 38. While bellows 22 is expelling, bellows 24 is being refilled through check valve 36. When bellows 22 reaches point 52 any suitable switching arrangement 30 causes the gas control valve to recycle and direct pressurized gas back to housing 28. An accumulator 56 is attached to outlet line 44 in order to dampen the pressure pulses during the gas control valve cycling period. The fiow/ refill cycle continues for the length of predetermined desired time by a timer (not shown) suitably attached to control valve 14.

Although only one type switching arrangement 30', 32 is shown any suitable alternative may be used. For example, a plurality of switches may be used on each housing in place of switching arrangements 30 and 32. Furthermore, check valves 34, 36, 38 and 40 may be replaced by valves which are controlled by a suitable switching arrangement.

MODE OF OPERATION Operation is begun by liquid loading which is accomplished by evacuation of the liquid side of the bellows, then bleeding in the liquid from supply 43 to get a filled system. The bellows fill as the gas side of the bellows are vented to ambient.

The flow operation begins by supplying a regulated source of gas to the gas control valve 14. The control valve 14, for example, directs the gas into housing or tank 28 and simultaneously vents the gas side of tank 26 through vent 19. The above operation (as clearly shown in the figure) closes check valves 36 and 38 and supplies the pressurized liquid to the outlet 46 through check valve 40. As the liquid is supplied out of outlet 46, bellows 24 moves downward to the position shown in the figure, while bellows 22 moves upward. At a predetermined point 48 the bellows 24 actuates switch 32. The actuation of switch 32 causes the gas control valve 14 to cycle in order to supply pressurized gas to the gas side of bellows 22 and vent the gas side of bellows 24 through vent 21. This operation closes check valves 34 and 40 (in a manner not shown) and supplies pressurized liquid to outlet 46 through check valve 38. As bellows 22 reaches point 52 it actuates switch 30 which in turn causes gas control valve 14 to recycle and direct pressurized gas back to tank 28. An accumulator 56 dampens the pressure pulses during the gas control valve cycling period.

In other words, as bellows 24 is expelling through check valve 40, bellows 22 is filled through check valve 34, and as bellows 22 is expelling through check valve 38, bellows 24 is filling through check valve 36.

Although the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments, such as other switching arrangements, all within the spirit and scope of the appended claims.

What is claimed is:

1. A pneumatic bellows pump comprising a pressurized gas source, a control valve connected to said source, at least two housings, each of said housings having an aperture in the top thereof, each of said apertures being directly connected to said control valve, each of said housings further containing a bellows therein, each of said bellows having an opening at the bottom thereof, a fluid source, a pair of tubes connecting said fluid source to the bottom openings in each of said bellows, each of said pair of tubes having a pair of check valves therein, one valve of each of said pair of check valves being closed simultaneously with the other valve of each of said pair of check valves being open, a switch mounted on each of said housings, said switches being in operative relationship with said bellows and operably connected to said controlvalve whereby activation of either of said switches cycles said control valve so as to alternately pressure and vent each of said housings.

2. A pneumatic bellows pump as defined in claim 1 whereinsaid gas is nitrogen.

3. A pneumatic bellows pump as defined in claim 2 wherein said bellows are made of a corrosive resistant material.

4. A pneumatic bellows pump as defined in claim 3 wherein an accumulator is located adjacent said outlet.

5. A pneumatic bellows pump as defined in claim 4 wherein said valve means has at least one vent therein.

References Cited UNITED STATES PATENTS 862,867 8/1907 Eggleston 103-15'2 1,696,825 12/1928 White 103-44 2,212,667 8/1940 Mager 103-152 2,419,993 5/1947 Green et al. 103152 2,673,525 3/1954 Lucas 103152 2,703,055 3/1955 Veth et al. 103-152 ROBERT M. WALKER, Primary Examiner U.S. Cl. X.R. 417-540, 394 

